In recent years, as an element used for a nonvolatile memory cell, a MONOS type nonvolatile memory cell (hereinafter, simply referred to as an MONOS memory in some cases) using a nitride film as a charge storage layer has attracted attention. As the MONOS type nonvolatile memory cell, not only a memory cell with a single transistor structure but also a memory cell with a split gate structure having a two-transistor structure having a selection gate electrode and a memory gate electrode has been proposed.
The selection gate electrode and the memory gate electrode, which configure the MONOS memory with the split gate structure and which are adjacent to each other on a semiconductor substrate, are electrically insulated from each other by an insulating film that is interposed therebetween and includes a charge storage layer. When the MONOS memory is operated, information is stored and deleted by inputting/outputting electric charges to/from the charge storage layer.
International Patent Publication No. WO2010/082389 (Patent Document 1) describes that short circuit between the selection gate electrode and the memory gate electrode which are adjacent to each other is prevented by providing an insulating film on the selection gate electrode which configuring the MONOS memory with the split gate structure.